An array of transducers receives the signals emitted by a localized
source in a scattering acoustic medium. The recorded signals can be used
either in a time-reversal (TR) process in order to refocus acoustic energy
back onto the source, or in a matched field imaging (MF) process in order
to estimate the source location. In TR the signals are time-reversed
and emitted into the physical medium whereas in MF they are
time-reversed and back-propagated numerically in a fictitious
homogeneous medium. Given the range (distance from the array)
of the active source we study here the cross-range resolution in
these two processes. As expected, multiple-scattering enhances
the refocusing resolution in TR but it degrades resolution in the
estimation of the source location with MF. We introduce a robust
procedure for estimating the resolution gain (resp. loss) in TR
(resp. MF), in weakly scattering random media. Direct numerical
simulations in the ultrasound regime show that our
estimation method is accurate and effective.
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